The present invention relates to coating compositions suitable as primers. The present invention also relates to substrates having a multilayer coating, one of the layers being a primer composition.
In the production of coating compositions for structural building components such as metal building panels there are often competing goals to be reconciled. On the one hand, there is the need for good durability properties such as color retention, mar resistance and chalk resistance in the face of severe weather conditions as well as corrosive industrial pollutants. On the other hand, there is the requirement of good flexibility to facilitate fabrication of the metal without loss of the coating's adhesion.
In the coil coating area the difficulties are exemplified by the conventionally utilized plastisol based coating compositions. Plastisols are desirable coating vehicles from the standpoint of fabrication, however, they exhibit poor durability, color retention, chalk resistance and dirt resistance. As a result, compromises must often be made either in terms of ultimate film properties or workability of the coated substrate.
There is a need, therefore, for a way to achieve a coating which results in not only good durability, but also workability and ease of fabrication of the coated substrate.